Apparatus for forming powder metallurgy parts



Oct. 9, 1951 R. P. SEELIG APPARATUS FOR FORMING POWDER METALLURGY PARTS5 Sheets-Sheet l INVENTOR. Richard 1 166612 BY MZMWQ ATT RNEYS Oct. 9,1951 R. P. SEELIG 2,570,989

APPARATUS FOR FORMING POWDER METALLURGY PARTS Filed Feb. 15, 1944 3Sheets-Sheet 2 INVENTOR. Richard 1? See! BY @XMM +4 ATTOR N IYS Oct. 9,1951 j R. P. SEELIG APPARATUS FOR FORMING POWDER METALLURGY PARTS FiledFb. 15, 1944 3 Sheets-Sheet 3 HHIIIIHIIIHH...

mm wm T e E DNA VS T MB Z m a m a Patented Oct. 9, 1951 2,570,989crreservs; For owers METALLURGY PARTS Richard 3-. Seel El t, N- Y s s rmesne. assignments, to General Bronze Qorpo ra ion ard nv i a. co portion New Yo k Application February 15, 1944, Serial No. 522,530 1 Claim.(o1, names),

This invention relates to, an apparatus for formingpowder metallurg-yparts of intricate des gn.

The invention has for an object to compress metal powders into parts ofvarious shapes so that the parts will have substantially uniform densitythroughout their mass and which will be substantially free of cracks orlaminations.

The. invention has for a further object the ejection of the formed andcompressed metal parts from the forming die while maintaining the. sameunder-such pressure as will prevent any substantial injury to the formedpart.

I have illustrated the mechanical phase of my invention as embodied in amechanically operated press, but it is to be understood that it is notlimited to such a press for the press may be operated by hydraulic orother pressure.

In the drawings;

Figures 1 through 6 are views, partly in section and partly inelevation, illustrating-the mechanism and successive steps of theoperation of the press; and

Figure 7 is a diagrammatic view of the driving means for the cams.

The press includes a base I having table 2 with a cross head 3 and a diesupporting portion which is adapted to receive and support a die 5 ctsuitable form for the powdered metal part that isto be formed. This dieis secured in place in the table. by a clamping ring 6 of conventionaldesign. I- have illustrated the powdered metal within the. die inFigures 1 through -6 at I, regardless of its state of compression. Aplunger 3 is mounted for vertical sliding movement in a bearing 9 in thebase and carries a lower punch l0 atits, upper end which is in alignmentwith and adapted to enterthe opening of the die 5.

A plunger extension I I is rigid with the plunger 8: and may havescrew-threaded engagement therewith. This plunger extension projectsdownwardly therefrom and loosely into an opening [2 in thebase l'. Theextent, of downward movement of the plunger 8 and its punch I0 islimited b a stop nut l3.

The upward and downward movement of the plunger- 8 and its punch L0 iscaused and controlled by a cam M. which is driven b any suitable sourceof power such as a prime mover I5 through gears l6, H and; 5;. A camroller- [.9 carried by a bell crank lever 20 rides upon the We i: theam. it. a d. is he i con a t her with. y a. p i t thaw p ir ntio ie presat d. n. th ew ng inis b l crank. ever, is givetee. at 21. 9, he -areasbees. i. re s r- 2. otal-ly connected to a link 22 which, in turn, ispivoted at 23 to a rocker lever 24. This rocker lever 24 is pivoted at25 to the base I. One arm 26 of the lever 24 is loosely connected to theplunger extension H as at 21 and is adapted to operate against twoadjustable abutments 28 and 29 on the plunger extension H. I have shownthese. two. abutments in the form of adjustable 7 driven in a definiterelation to the cam 14 through nuts on the plunger extension and it willbe understood that by adjustment of these nuts the punch it, will bemoved either upwardlyor-dowm wardly in relation to the. arm 26. of thelever 24, wth thev result. that the stroke of the punch may lie-varied.

Moreover theplunger 8: and its. punch Ht may be removed and replaced byanother plungerand lower punch as the. occasion requires.

An upper punch 31!. is located above thelower punch H1 and the dieopening and carried by a slide 30 which, is mounted for upward anddOWn". ward sliding movements in a bearing 3.1. in the cross head: 3.Lhis slide. 39* is provided with a chamber 32 which is closed at itsupperend by a plate. 3:3 having an orifice 34 therein, which plate is,pgsitively attached to' the slide. A rod 35.. having a roller on itsupper end which rides in a groove a cam 36; extends through the.or-ific-e oi the plate 33 into, the. chamber 32;. A collar 31, rigidwith the rod 35, is lofialted within the chamber 32 and is provided.witha boss 3.8 The distance between the upper face of the co1la .31,which is, adapted to engage the lower face of the plate 3,3;andthe lowerend of the. boss 38;, which s adap ed o. engagethe lower end of thechamber 3,2; is less than the. distance between these two portions orthe slide.

A spring 3;9- surrounds the. boss 3.8 and, operating against the lowerface of the chamber 32 and the lower face of the collar 33 normallyurgesthe. rod 35, upwardly and the. end of the boss 3&8v out, of contactwith the adjacent end of the chamber 3210f the slide 30.".

. The. cam 36; is mounted on a shaft 48; which is connected to. theprime mover i5: and carries the gear Hi; Bythis arrangement the cam- 36.is

the relationship of gear [6, the, gear Isl carried by the shaft lz'l'and; the gear it: which is carried bytheshaf-t ltf-ofithecami l.

Describingnow the operation of this embodimerit-.- Qfi the mechanicalphase of my invention, and: referring to.- Figures 1 through 6, when theparts; are in the positions illustrated in Figure l, with, the lowerpunch IJll closing the lower end 5.5, of the. die c-avtty, andtheupperpunch 30 in its 3 raised position, the die cavity is filled withthe metal powder indicated at 1. When the cams l4 and 36 are set inmotion they both turn clockwise, as shown in the drawings, and becauseof the fact that the roller [9 contacts a concentric face during theinitial part of the movement of the cam, the lower punch remainsstationary. However, the upper slide with its punch 30 will immediatelystart to move downwardly. Due to the increasing distance of the camtrack from the center of rotation of the cam 36, the camsare so timed intheir rotation that as soon as the upper punch 30 enters the die thelower punch begins to move upwardly.

In the embodiment illustrated the die is of such form that the flange ofthe part I that is being formed of the powdered metal is less deep thanthe lower shank of the part. Because of this the upper punch will travelmore slowly into it portion of the die cavity than will the lower punchID as soon as the upper punch enters the die.

As the upper punch meets the resistance of the powdered metal within thedie cavity, the continued rotation of the cam 36 will compress thespring 39 so that the lower end of the boss 38 will engage the lowerface of the chamber 32 and there will be a positive connection betweenthe rod 35 and the upper slide with its punch 30;

The parts in this relationship are illustrated in Figure 3 of thedrawing.

The relative movements of the upper and lower punches described aboveare such that both punches will reach their maximum pressuresimultaneously in the position shown in Figure 3 of the drawing and thepowdered metal will be completely compressed into a part having a flangeand a shank as illustrated in this figure.

As soon as both of the upper and lower punches reach the maximumpressure positions shown in Figure 3, the cam 36 will have rotated to aposition such that the rod 35 will move upwardly under the influence ofthe spring 39, while the upper punch remains in its lowered position.This upward movement of the slide creates a space between the boss 38and the adjacent face of the chamber 32 of the upper slide so thatupward movement of the upper punch 30 is resisted by the springpressure.

During the upward movement of the upper slide with its punch 30 underthe action of the cam 36 and the rod 35 the lower slide 8 with its punchl0 moves upwardly under theinfluence of the cam 14 and during thismovement of the two punches the metal part 1 will be moved upwardlyinitially under the lateral pressure of the die and under thelongitudinal yielding pressure created by the spring 39.

As the punches continue their upward movement with the metal part 1 thusclamped between them, the pressure is maintained constant until theupper face of the lower punch 10 is flush with the surface of the dieand the metal part no longer receives the lateral pressure ofthe die 5.

The relative positions of the parts when the lower punch reaches theuppermost end of its troke is illustrated in Figure 4 of the drawings.

When the parts reach this position the cam 36 moves the upper slideupwardly, while the cam l4 permits the lower punch ID on the plunger 8to remain in its uppermost position with the metal part supported on theupper end of the lower punch, as shown. inFigure 5, so that it part willnot be fractured or weakened.

may be removed by hand or automatic means.

The continued movement of the cam l4 permits the lower plunger 8, withits punch ID, to move back into it lowermost position, as illus tratedin Figure 6 of the drawings, where it will close the lower end of thedie cavity and the cavity may be fllled for the second cycle ofoperations.

It is to be noted that the groove of the cam 36 isso formed that whenthe upper slide is being moved upwardly by the cam and the spring 39provides a yielding connection between the slide and the rod 35 therewill be a gradual drop in pressure on the compressed metal part by theupper and lower plunger until the metal part is completely ejected fromthe die and ready for removal.

Thus it will be seen that the metal powder is first compressed withinthe die cavity by pressures exerted from above and below, and when thedie cavity is of the form illustrated in the drawings, with a thinflange zone and a deeper shank zone, the maximum pressure on the flangezone will be reached simultaneously with the reaching of the maximumpressure on the shank zone. The result of this will be the production ofa powdered metal part having a substantially uniform density.

After this compression the positive pressure exerted on one end of thepowdered'metal part will be transformed into a yielding pressure.However, the pressure exerted on both ends of the powdered metal partwill continue to exist during the removal of the part from the diecavity at which time the pressure on the part will be relieved, but thepart will remain supported by one of the pressure creating forces untilit has been removed for the sintering operation.

This method insures the production of powdered metal parts which willhave substantially uniform density and which will be relieved of thecompressive forces in such manner that the The method insures thesubstantially uniform density of the powdered metal part irrespective ofthe differences in the depth of the various zones of the part.

I have illustrated the upper and lower punches as being operated bymechanical cams and gearing, and as having a yielding connection betweenthe upper punch and its cam mechanism, but it is to be understood thatthis mechanical operation may be supplanted. by a hydraulic system whichis the equivalent of the mechanical system here shown.

Moreover it will be realized that certain of the parts may behydraulically operated while the others are mechanically operated.

While I have illustrated and described the particular embodiment of thestructural phase of my invention, I do not wish to be limited to thedetails thereof or to the particular structure of the embodiment exceptin so far as this is made necessary by the claim.

What I claim is:

In an apparatus for forming powder metal parts, a die having a powderedmetal receiving cavity, a lower punch constructed and arranged to movewithin said cavity, an upper punch constructed and arranged to move to,away from and within said cavity, means for moving said lower punchwithin said cavity, the upper punch hav ing a chamber therein closed atboth of its ends, a rod extending into said chamber and freely movabletherein and having a collar thereon adapted to engage a wall at one endof said chamber. the distance between said collar and the other wall ofsaid chamber being greater than the length of the rod from said collarto its adjacent end, a coil spring within said chamber interposedbetween said collar and the last mentioned wall of said chamber tonormally hold the adjacent end of said 'rod spaced from said wall andsaid collar in contact with the wall of the chamber adjacent to thecollar, and means for reciprocating said rod.

RICHARD P. SEELIG.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Pennock Mar. 25, 1873 LeonhardtJul; 12, 1904 Johnson June 9, 1925 Claus Apr. 12, 1927 Davis et al. Aug.'7, 1928 Fitzgerald July 9, 1929 Davis Aug. 23, 1938 Whipple Aug. 19,1941 Wellman -a-== =-'c==-==- Oct. 14, 1941 Morin -51-.. Oct. 2'7, 1942Kili'tz l Sept. 5, 1944 Langhammr Nov. 19, 1946 Selig 1 -1. Sept. 14,1948

